Modern motor vehicles are characterized by a plurality of electronic systems such as electronic injection and ignition controls and/or ABS systems. Additional electronic systems must be introduced in order to in the future satisfy ever increasing requirements as to: compatibility with respect to the environment, wear, safety and/or comfort of the motor vehicles. The most important systems are the following: electronic engine power control systems (the so-called electronic gas system), road-speed control systems, anti-skid or engine braking torque control systems (ASR/MSR) and/or electronic transmission control systems as well as chassis control systems, steering systems including electronic rear-wheel steering, control systems for maintaining distance between motor vehicles, navigation systems and/or traffic guidance systems.
In this connection, it is to be noted that the above-mentioned component systems intervene at least in several subranges of their function on the output power of the motor vehicle, for example, the transmission control during gear shifting operation, the ASR-system for anti-skid control, a control system for controlling the distance to a motor vehicle travelling forward of the subject vehicle and the like. This further increases the complexity of the total system for controlling the motor vehicle. An optimal cooperative relationship between the component systems is necessary, however, to obtain a satisfactory control of the motor vehicle. It is an object to reduce the cross coupling between the individual component systems and thereby obtain an independent application and control of each component system.
A first step in this direction is disclosed in U.S. Pat. No. 5,351,776. Here, and proceeding from a driver command, a hierarchically arranged system structure is proposed wherein interface positions are defined between the individual logic component systems via which data with respect to one of the variables are transmitted. This variable is to be adjusted by the next-lower hierarchical level. Data with respect to a motor torque desired value are transmitted for adjusting the motor power via the control of the air supplied, the fuel metered as well as the ignition time point. A detailed description of this interface position, which is directed toward the motor control system, is not provided in the above-mentioned patent application.